This study proposes to look for genetic linkage and/or disease association between various genetic markers and the 2 cleft entities, cleft lip with or without cleft palate, CL(P), and isolated cleft palate, CP. These 2 disorders are etiologically different but not individually homogenous. Subjects for study will be Danes residing in the Copenhagen area and will be selected from the pedigrees on file at Indiana University covering 5000 plus cleft persons born in Denmark from 1941-1971. Two study groups (comprising about 600 persons total) will be employed: familial CL(P) and CP. Previous studies support the rationale for considering sporadic cases to be of different etiology from the familial or multiplex ones. A large series of biochemical markers will be typed in this cleft population from samples of leucocytes, erythrocytes, serum, urine and saliva. Linkage between the marker and cleft phenotypes will be looked for using the computer program LIPED which contains the likelihood of whole pedigrees even in situations where the mode of inheritance is not simple Mendelian as is the case with clefting.